Safety device for vehicle lifts



Dec. 19, 1961 K. L. RACELY SAFETY DEVICE FOR VEHICLE LIFTS Filed May 8, 1961 %%%%%%%%%w y Y FIG.

FIG. I

INVEN TOR.

KERMIT L. RACELY United States Patent G F 3,013,635 SAFETY DEVICE FOR VEHICLE LIFTS Kermit L. Racely, Memphis, Tenn., assignor to Dover Corporation, Washington, D.C. Filed May 8, 1961, Ser. No. 108,476 Claims. (Cl. 187--8.49)

This invention relates to a safety device for vehicle lifts and the like to prevent the accidental lowering thereof.

This invention is particularly useful in a so-called n0nrotator leg of the type which includes telescoping inner and outer members arranged so that the inner member is attached to the load supporting structure of the vehicle lift for vertical movement therewith and the outer member is mounted in a fixed position usually below the floor level. T he safety device of the present invention is carried in the inner member and the non-rotator leg and arranged so that the latching element thereof, when in a latching position, extends above the outer member to prevent the inner member and therefore the load supporting structure from being accidentally lowered or accidentally falling, since the latching element will engage the top of the outer member to prevent such movement. When it is desired tolower the supporting structure, the latching element is movable into a resetting position, where the latching element is positively locked until lowered into the outer member.

There have been other types of safety devices heretofore contemplated for preventing accidental lowering of vehicle lifts. For example, one type of device operates on a movement of the center of gravity of the latching element from one side of a dead center position to the other side in moving from a latching position to a resetting position. In this type, the latching element merely rests in the resetting position under the influence of gravity. There is no positive locking of the element in the resetting position and it could be accidentally moved into the latching position by a transverse force exerted thereagainst. In contrast to this, the latching element of the present invention is arranged so that the center of gravity thereof is so related to its pivot axis that the latching element has a tendency at all times to pivot in one direction, and it isheld in the resetting or locked position against such pivoting movement by positive means. To uniock the latching element it is necessary for the latching element to move upwardly so that there is little likelihood that a transverse force would accidentally unlock the latching element, but instead it is unlocked at the proper time by engagement with the outer member which causes the latching element to move upwardly. In other words, the center of gravity of the latching element of the present invention does not shift from one side of the pivot axis to another but stays on the same side thereof and is held against pivot by locking means adapted to be only unlocked by engagement with the outer member upon lowering of the vehicle lift. The above mentioned locking means of the present invention comprises a hook provided on the latching element which is engageable with a pin to lock the latching element in place.

Thus, one of the objects of the present invention is to provide an improved and efficient safety device for vehicle lifts and the like.

A further object is to provide such a device that is positive acting and completely reliable.

A further object is to provide such a device that is simple in construction and easy to operate.

A further object is to provide in such a device a latching element that, because the latching element has a tendency to pivot in one direction, is definite in its movements from a locked position to an intermediate position and thence to a latching position.

Patented Dec. 19, 1961 ice A further object is to provide such a device that is fully automatic in operation except for the manual locking required before the vehicle lift is lowered.

A further object is to provide such a device in which is provided locking means comprising a hook engageable with a pin to lock the latching element in place.

The means by which the foregoing and other objects of the present invention are accomplished and the manner of their accomplishment Will be readily understood from the following specification upon reference to the accompanying drawings, in which:

FIG. 1 is a schematic fragmentary view of a vehicle lift incorporating the improved safety device of the present invention.

FIG. 2 is an enlarged fragmentary sectional view of the device taken as on the line 11-11 of FIG. 5, but showing the latching element in a locked position.

FIG. 3 is a view similar to FIG. 2 but showing the inner member lowered relative to the outer member and showing the latching element in an intermediate position.

FIG. 4 is a view similar to FIG. 2 but showing the latching element in a latching position.

FIG. 5 is a side elevational view, viewed as from the line V- V in FIG. 4.

FIG. 6 is a fragmentary sectional view taken as on the line VI-VI of FIG. 4.

Referring now to the drawings in which the various parts are indicated by numerals, the safety device 11 of the present invention is shown in connection with a fluid operated lift, which is indicated in general by the numeral 13 and which comprises the usual cylinder 15 firmly embedded in a foundation 16, as concrete or the like, and having a vertically movable piston 17 carrying a load or vehicle supporting structure 19. The fluid system for raising and lowering piston 17 is not shown since it forms no part of the present invention and comprises any suitable Well-known means whichutilizes a suitable fluid such as the combination of hydraulic and air pressure or hydraulic fluid alone.

Fixedly secured in the foundation 16, adjacent and parallel to cylinder 15, is an outer member 21, preferably formed from a pipe or tube smaller in diameter than cylinder 15 and into which an elongated inner member 23, preferably formed from a still smaller pipe or tube, is telescoped. Inner member 23 is rigidly secured adjacent the upper end thereof to vehicle supporting structure 19 and slides freely in the outer member as piston 17 is raised and lowered. Thus, outer member 21 is mounted below the path of movement of supporting structure 19 with the upper end of the outer member preferably being even with the ground or floor level 25. The above described combination of inner member 23 and outer member 21 is commonly known as a non-rotator for preventing undesired rotation of supporting structure 19, and is designated in general in the drawings by numeral 27. The safety device 11 of the present invention is preferably incorporated in non-rotator 27 to cooperate between members 21, 23, as will now be described.

Safety device 11 comprises in general a latching element 29 pivotally supported in inner member 23 by a horizontal shaft 31 that extends through an elongated slot 33 provided in the latching element. The opposite ends of shaft 31 are supported in inner member 23 as. by means of spaced parallel vertical plates 35, 36 disposed on opposite sides of latching element 29. Plates 35, 36 form part of a housing'37 that is preferably cast in one piece and includes laterally spaced side meme 23 so that side members 39, 41 are flush with inner member 23 when the housing is placed in the inner member, as hereinafter described. It will be understood that side members 39, .1 interconnect the vertical plates 35, 36 to establish the rigid housing. In addition, it will be understood that to assemble housing 37 in inner member 23 it is only necessary to cut transverse openings 43, 45 in inner member 23 to conform to the outline of housing 37. Then the housing 37 is slipped into place in inner member 23 and welded therein to fixedly mount the housing in the inner member. Vertically elongated transverse openings 47, 49 are respectively provided in side members 39, 41, which openings are in substantially transverse alignment with the space 51 between plates 35, 36 so that a transverse passage is provided through inner member 23 in housing 37.

Latching element 29 is provided adjacent one end thereof with a hook 53, which hooks over a horizontal pin 55, extending between and supported by plates 35, 36 to positively hold the latching element in a locked position, as shown in FIG. 2. Pin 55 is preferably located in transverse opening 47 adjacent the upper part thereof but spaced from the upper end of the opening. Also, pin 55 is preferably located at a higher position in housing 37 than shaft 31. When latching element 29 is in said locked position the end portion 57 of the latching element adjacent hook 53 extends outwardly beyond the exterior of inner member 23 through transverse opening 47 above outer member 21 and the remainder of the latching element is on the interior of inner member 23. It will be understood that said locked position can only occur when inner member 23 is in positions sufficiently raised relative to outer member 21 so that the end portion 57 can extend outwardly from the exterior surface of inner member 23. It should be pointed out that said locked position is the position into which the latching element 29 is placed, in a manher later to be described, preparatory to lowering vehicle supporting structure 19. When vehicle supporting structure 19 is lowered with latching element 29 in said locked position, it will be understood that end portion 57 will engage the upper end 59 of outer member 21 which will cause hook 53 to be lifted relative to pin 55 to unlock the latching element 29, whereupon the latching element will rotate clockwise as viewed in FIGS. 2 and 3 until the latching element moves through transverse opening 49 and into engagement with the interior of outer member 21, which stops the latching element in an intermediate position shown in FIG. 3. It will be seen in this figure that the area of latching element 29 indicated as at 61 has engaged the inner surface of outer member 21. It will be understood that the upward lifting of hook 53, as above described, is possible since slot 33 is elongated in a direction generally extending away from pin 55 and generally away from portion 63, which is the portion of the latching element defining the end ofthe slot 33 and upon which the latching element normally pivots. It should be pointed out that when end portion 57 engages upper end 59, the major portion of the latching element is inside of outer member 21 so that the outer member will limit pivot of the latching element, as above described. In addition, it should be pointed out that the relationship of the center of gravity of latching element 29 to its horizontal pivot axis about shaft 31 is such that the latching element will pivot in one given direction. In other words, as viewed in FIGS. 2, 3 and 4, the center of gravity of latching element 29 is to the right. of shaft 31 so that the latching element is urged at all times to pivot clockwise. Although, in the safety device 11 shown in the drawings, the force of gravity is the means for pivoting the latching element in said one direction, it will be understood that other means such as springs or the like may be employed to pivot the latching element in said one direction without departing from the spirit and scope of the present invention. Bearing in mind the above described tendency of latching element 29 to pivot in said one direction at all times, the unlocking operation of hook 53 from pin 55 is better understood since it is apparent that once the hook has been lifted upwardly by contact with outer member 21, the tendency of the latching element to pivot will cause the completion of the unlocking operation. In addition, it will be seen that although the hook 53 is efficiently and effectively unlocked by eng ment with outer member 21, any accidental unlocking by a horizontal force striking the end portion 57 will not be likely since an upward force is required.

As long as latching element 29 is down inside of outer member 21, as shown in H6. 3, the latching element will remain in said intermediate position with the latching element in the area 61 thereof sliding on the inside of outer member 21 when the inner member is moved- However, when the vehicle supporting structure 19 is subsequently moved to a raised position so that area 61 is above outer member 21, the area 61 will no longer have the inside of outer member 21 to rest on and will therefore pivot clockwise. Thus, as the upward movement of inner member 23 is continued, latching element 29 continues to pivot clockwise until the lower edge 65 of the latching element contacts the portion 67 of member 4-1 that defines the lower end of opening 49 and serves to stop the latching element in said latching position, shown in H6. 4. It will be understood that this movement from said intermediate position to said latching position will take place since, as heretofore described, the latching element 29 has a tendency to move in a clockwise direction. It will be seen in FIG. 4 that when latching element 29 is in said latching position, portions of the latching element, i.e. portions at 69 and at 61, extend outwardly in opposite directions respectively through transverse openings 47, 4-9 above outer member 21 to limit subsequent accidental downward movement of inner member 23 and vehicle supporting structure 19 since any downward movement would be limited by engagement of portions 61 and 69 with upper end 59, with such a condition being illustrated in FIG. 1. it should be noted that in the normally raised position of vehicle supporting structure 19, latching element 29 is usually spaced above upper end 59, as shown in FIG. 4.

The exact shape of latching element 29 is not critical, although the relationships of the center of gravity, pivot points, etc. should be maintained. The shape shown in the drawings, however, is the preferable shape since it has been found to operate exceptionally well, and the lower edge 65 is preferably straight and preferably horizontal when latching element is in said latching position, as best seen in FIG. 4.

Thus, from the foregoing, it will be seen that latching element 29 automatically moves from a locked position, to an intermediate position, and thence to a latching position. Therefore, there is no possibility that the operator of the vehicle lift will forget to move the latching element into a latching position when the vehicle supporting struc' ture is subsequently raised after having been lowered.

It will be understood that latching element 29 is easily and quickly returnable to the locked position when the operator desires to lower vehicle supporting structure 19. This is easily done by either kicking the latching element 29 or by moving it with other means such as with the hand or with an instrument to pivot the latching element counterclockwise until hook 53 once again engages pin 55. To facilitate this movement of end portion 57 over pin 55, the end portion is preferably arcuately shaped as at 73.

From the foregoing description it will be understood that an improved and eiiicient safety device for vehicle lifts and the like is provided. In addition, such a device is provided which is positive acting and completely reliable. Further, such a device is provided which is simple in construction and easy to operate.

Although the invention has been described and illustrated with respect to a preferred embodiment thereof, it is to be understood that it is not to be so limited since changes and modifications may be made therein which are within the full intended scope of this invention as hereinafter claimed.

I claim:

1. In a vehicle lift having a vertically movable load supporting structure and having telescoping inner and outer members with said inner member being fixed to said load supporting structure and said outer member being mounted below the path of movement of said supporting structure, a safety device cooperating between said members to prevent accidental lowering of the load supporting structure comprising a latching element including a hook, said latching element being provided with an elongated slot therethrough, said inner member being provided with transverse openings; a shaft carried in said inner member and extending through said elongated slot to pivotally support said latching element for pivot about a horizontal axis between locked, intermediate and latching positions; said latching element being arranged so that the force of gravity at all times tends to urge said latching element to pivot in one given direction, a pin carried by said inner member, said hook being removably engaged on said pin to positively hold said latching element in a locked position against the force of gravity tending to carry the latching element in said one given direction, when in said locked position a portion of said latching element extending outwardly through one of said transverse openings above said outer member Whereby when said inner member is lowered into said outer member said latching element portion is engageable by said outer member, said latching element being arranged so that when said latching element portion is engaged by said outer member a major portion of said latching ele ment is inside of said outer member, said pin and said latching element being arranged so that engagement of said latching element portion by said outer member is effective to urge said latching element portion upwardly and in cooperation with the tendency of pivot of said latching element is effective to unhook said hook from said pin whereby the force of gravity causes said latching element to continue to pivot in said one direction until in said intermediate position in which said latching element extends into one of said transverse openings and slidably rests against the inside of said outer member, subsequent raising of said inner member so that said latching element no longer slidably rests on the inside of said outer member being eiiective' to cause said latching element to pivot in said one direction from said intermediate position towards said latching position, means for limiting pivot of said latching element to stop said latching element in said latching position wherein portions of said latching element extend outwardly in opposite directions respectively through said transverse openings above said outer member to limit subsequent accidental downward movement of 7 said inner member relative to said outer member 2. In a pair of vertically disposed telescoping mem bers including an inner member slidably mounted in an outer member, a safety device cooperating between said members to prevent accidental lowcringof said inner member relative to said outer member com-prising a latching element including a hook, said latching element being provided with an elongated slot therethrough, said inner member being provided with transverse openings; a shaft carried in said inner member and extending through said elongated slot to pivotally support said latching element for pivot about a'horizontal axis between locked, intermediate and latching positions; said latching element having a tendency atall times to pivot in one given direction, a pin carried by said inner member, said hook being removably engaged on said pin to positively hold said latching element in a locked position against the tendency to pivot in said one given direction, when in said locked position a portion of said latching element extending outwardly through one of said transverse openings above said outer member whereby when said inner member is lowered into said outer member said latching element portion is en gageable by said outer member, said latching element being arranged so that when said latching element portion is engaged by said outer member a major portion of said latching element is inside of said outer member, said pin and said latching element being arranged so that engagement of said latching element portion by said outer member is effective to urge said latching element portion upwardly and in cooperation with the tendency of pivot of said latching element is effective to unhook said hook from said pin whereby said latching element continues to pivot in said one direction until in said intermediate position in which said latching element extends into one of said transverse openings and slidably rests against the inside of said outer member, subsequent raising of said inner member so that said latching element no longer slidably rests on the inside of said outer member being eifective to cause said latching element to pivot in said one direction from said intermediate position towards said latching position, means for limiting pivot of said latching element to stop said latching element in said latching position wherein portions of said latching element extend outwardly in opposite directions respectively through said transverse openings above said outer member to limit subsequent accidental downward movement of said inner member relative to said outer member.

3. In a pair of vertically disposed telescoping members including an inner member slidably mounted in an outer member, a safety device cooperating between said mem-' bers to prevent accidental lowering of said inner mem ber relatlve to said outer member comprising a latching element including a hook, said inner member being provided with transverse openings; means pivotally supporting said latching element in said inner member for pivot about a horizontal axis between locked, intermediateand latching positions; said latching element having a tendency at all times to pivot in one given direction, means carried by said inner member releasably engaged with said hook to positively hold said latching element in a locked position against the tendency to pivot in said one given direction, when in said locked position a PCT? tion of said latching element extending outwardly through one of said transverse openings above said outer mem: b-er whereby when said inner member is lowered into said outer member said latching element portion is engageable by said outer member, said latching element being arranged so that when said latching element portion is engaged by said outer member a major portion of said latching element is inside of said outer member, said latching element being arranged so that engagement of said latching element portion by said outer member is effective to urge said latchi g element portion upwardly and in cooperation with the tendency of pivot of said latching element is efiective to release said hook Where,- by the force of gravity causes said latching element to continue to pivot in said one direction until in said intermediate position in which said latching element can tends into one of said transverse openings and slidably rests against the inside of said outermernber, subsequent raising of said inner member so that said latching ele= ment no longer slidably rests on the inside of said outer member being eflective to cause said latching element to pivot in said one direction from said intermediate position towards said latching position, means for limiting- Pivot 9 aid at h e em nt o s ep said atc in l ment in said latching position wherein portions of said latch-ing element extend outwardly in opposite directions respectively through said transverse openings above said outer member to limit subsequent accidental downward 7 movement of said inner member relative to said outer member.

4. In a pair of vertically disposed telescoping members including an inner member slidably mounted in an outer member, a safety device cooperating between said members to prevent accidental lowering of said inner member relative to said outer member comprising a latching element including a hook; means pivotally supporting said latching element in said inner member for pivot about a horizontal axis between locked, intermediate and latching positions; said latching element having a tendency at all times to pivot in one given direction, means carried by said inner member releasably engaged with said hook to positively hold said latching element in a locked position against the tendency to pivot in said one given direction, said latching element being arranged to be moved upwardly relative to said inner member when said inner member is lowered into said outer member, upward movement of said latching element in cooperation with the tendency of said latching element to pivot being effective to disengage said hook and unlock said latching element.

5. in a safety device of the type incorporated in a vehicle lift non-rotator including inner and outer members and having a latching element pivotally supported in said inner member for movement between resetting, intermediate and latching positions; means for operating said latching element comprising a hook provided on said latching element, a pin carried by said inner member, said latching element having a tendency at all times to pivot in one given direction, said book being removably engaged on said pin to positively hold said latching element in a locked position against the tendency to pivot in said one given direction, said latching element being arranged to be moved upwardly relative to said inner member when said inner member is lowered into said outer member, upward movement of said latching element in cooperation with the tendency of said latching element to pivot being effective to disengage said book from said pin and unlock said latching element.

References Cited in the file of this patent UNITED STATES PATENTS 2,608,381 Pelouch Aug. 26, 1952 2,684,129 Jaseph July 20, 1954 2956,643 Halstead Oct. 18, l960 

